Final flow period sample capturing tool



Feb. 11, 1969 D. R. REARDON FINAL FLOW PERIOD SAMPLE CAPTURING TOOL Sheet Filed June '6, 1966 Feb. 11, 1969 D. R. REARDON FINAL FLOW PERIOD SAMPLE CAPTURING TOOL Filed June 6, 1966 %:2 Za A Sheet Feb. 11, 1969 D. R. REARDON 3,426,847

FINAL FLOW PERIOD SAMPLE CAPTURING TOOL Filed June 6, 1966 Sheet 3 of 4 z o i o 54 K K I: 0 i o r 464 k 0 O O O f I /7 E; O O

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Feb. 11, 1969 D. R. REARDON FINAL FLOW PERIOD SAMPLE CAPTURING TOOL Sheet Filed June 1966 W VE/V T02: DAN/EA R. REA/900M ATTO/QA/EX United States Patent 3,426,847 FKNAL FLOW PERIOD SAMPLE CAPTURING TOOL Daniel R. Reardon, Garden Grove, Califi, assignor to Cook Testing Co., a corporation of Nevada Filed June 6, 1966, Ser. No. 555,519 U.S. Cl. 166150 Int. Cl. Gtlln 1/10 1 Claim ABSTRACT OF THE DISCLOSURE Background of the invention It is conventional procedure in conducting a deep well oil formation test to employ a test tool assembly which is suspended from a drill string and includes, among other elements, and in order from the top downwards, a shut-in valve tool, a hydraulic valve tool, an open hole packer, a perforated tubing section and a graphic pressure recorder carrier.

The well is normally filled with rotary mud and the drill string is empty when going into the well, with the test tool assembly suspended thereon. The recorder graphically records the pressure of the surrounding fluid below the packer throughout the test. The perforated pipe admits said fluid upwardly through the packer, the hydraulic valve tool and the shut-in valve tool, into the lower end of the drill string, when said valve tools are both open, but the valves of these tools are both closed by the suspended weight of the tool assembly while the latter is being lowered into the well and while it is being withdrawn therefrom.

The first recording of significance is the Initial Hydrostatic Pressure, which is that of the fluids surrounding the recorder carrier when the latter first comes to rest on the bottom of the Well.

Each of the valve tools is telescopic, and is opened after the recorder carrier touches bottom, by cautiously continuing the lowering of the drill string. The shut-in tool offers little resistance to opening, and thus its valve opens before that of the hydraulic valve tool, which includes a hydraulic dash pot which delays its opening until suflicient downward pressure has been applied through the valve tools to the packer to set the latter in the well bore and thus pack-ofl the test area located between the packer and the Well bottom.

The setting of the packer and opening of the hydraulic valve tool completes the sealing-off of the test area at the bottom of the well from the column of rotary mud surrounding the drill string above the packer, and opens communication between the packed-off test area and the lower end of the empty drill string.

The next significant pressure in the test, known as the First Initial Flow Pressure, is now recorded.

After a short period during which the pressure in the test area below the packer generally increases slightly due to the rise in fluid level in the drill string, to a value termed the First Final Flow Pressure, the drill string is raised just that amount required to shut the shut-in valve tool, thus shutting in the fluid in said test area so as to develop the pressure latent in the adjacent formation due to fluids 3,426,847 Patented Feb. 11, 1969 ICE normally flowing from this formation into the well. When this pressure levels off, it is termed the First Initial Shut in Pressure.

The drill string is now lowered to open the shut-in tool, thereby reconnecting the test area with the interior of the drill string, the pressure thereupon dropping rapidly to a value slightly above the First Final Flow Pressure, and which is termed the Second Initial Flow Pressure.

A flow period of substantial length is now allowed to elapse, during which fluids entering the test area from the surrounding formation flow upwardly through the valve tools and into the lower portion of the drill string. The Second Final Flow Pressure is that recorded at the end of this period, and generally indicates that a sample of substantial magnitude has been received by the drill string.

At the conclusion of the last mentioned free flow period, the drill string is again lifted just enough to close the shut-in tool and seal off the test area against the escape of fluid therefrom. This causes the pressure to rise to a value generally the same or slightly less than the Initial Shut-in Pressure and is known as the Second, or Final Shut-in Pressure. This ordinarily concludes the pressure recordings taken in the formation test, and is followed by withdrawal of the drill string and tool assembly from the well.

When closed against a flow of fluid upwardly therethrough, the hydraulic valve tool opens an auxiliary valve which sets up a communication between the test area below the packer and the well bore just above the packer. This equalizes the pressures in these areas before pulling the packer, and facilitates the latter operation. It is of utmost importance, however, that this function of the hydraulic valve tool be not performed prematurely, but be reserved for the withdrawing of the equipment at the conclusion of the test. The tension in the drill string required to close the shut-in tool must therefore always be substantially less than that which will close the hydraulic valve tool to transmission of fluid upwardly therefrom and open the auxiliary valve for equalizing the pressures above and below the packer.

The closing of the shut-in tool at this stage of the testing operation closes a valve provided therein and prevents downward flow and loss of the fluid sample which has been received during the test in the lower portion of the drill string. Thus this sample is carried upwardly with the apparatus as it is withdrawn from the well. Often this withdrawal consumes enough time to cause a considerable portion of the gas entrained in the liquid of the sample to be lost from the latter during the withdrawal period. Segregation between the aqueous and oil constituents of the liquid also takes place in this sample, so that when an effort is made to analyze the sample by removing and testing a certain portion of the sample which is located close to the test tool assembly at the lower end of the string when this assembly arrives at the top of the well, an untrue picture is presented of the composition of the sample as a whole.

For this reason various expedients have been provided for embodiment within the test tool assembly for completely confining a small fragment of the sample which flows upwardly into the lower end of the drill string, so that this sample may be removed from the test tool assembly at the top of the well, and will give a true picture of the contents of the fluid which was delivered upwardly through the test tool assembly under free flow conditions during the test. The nature of the devices provided for this purpose have limited the size of the sample fragment thus captured at the bottom of the well to approximately 2,500 cubic centimeters. The chamber provided for capturing this sample portion had relatively large surface areas compared with the volume of the chamber, and when this chamber is opened at the top of the well and the sample portion drained therefrom, there is considerable loss due to the fact that the liquid of this sample portion adheres to said walls, and this is generally the heavier portions of the liquid, and thus distorts the picture produced by the analysis of that part of the sample which it is possible to recover from the tool containing this.

Summary of the invention It is an object of the present invention to overcome this difficulty by providing a tool which may be combined with the testing tool assembly above described and which will cooperate therewith in the ordinary manipulation of the tool assembly, above described, to capture and completely confine a portion of the fluid sample which has flowed upwardly through said tool assembly right at the end of the final flow period, which sample portion will be substantially greater than that captured by former devices provided for this purpose.

It is also an object of the invention to provide such an accessory tool which is connected at its lower end to the shut-in tool and at its upper end to the lower end of the drill string, and embodies a tubular section providing a sample capturing chamber having a substantial volumetric capacity, which is located directly adjacent the shut-in tool, and a bumper sub, or slip-joint, connected to the upper end of said tubular section and in turn connected to the lower end of the drill string, and which embodies a valve which closes in close coordination with the valve of the shut-in tool as the drill string is lifted at the end of the final flow period, so as to trap, between the closed valve of the shut-in tool and the closed valve of said slip-joint, a sample portion which fills said tubular section.

It is still another object of the present invention to provide such an accessory testing tool in which bleeder means is provided at the top and bottom of said tubular section, for directly connecting the same through pipes leading to analytical equipment at the upper end of the well, and thus separately releasing, under close control, into said analytical equipment, the gaseous, liquid and solid ingredients of said captured sample.

A still further object of the invention is to provide such an accessory deep well testing tool in which the above mentioned valve thereof functions either concurrently with the shut-off valve in the shut-in tool immediately therebelow, or slightly subsequent to the actuation of the valve in said shut-in tool. The purpose of this is to capture the sample occupying the tubular chamber of the tool and hold this until it is bled oil for analysis without any change in the pressure existing in that captive sample at the moment it was captured under free flow conditions during the final flow period of the test, at the bottom of the well.

Brief description of the drawing FIG. 1 is a diagram indicating the vertical relationship between FIGS. 2, 3 and 4 and the (a) series and (b) series figures which constitute successive downward extensions thereof.

FIG. 2 is a diagrammatic vertical sectional view of a preferred embodiment of the oil tool of the invention with the parts thereof in the relative positions which they occupy when said tool is telescopically extended, as when being lowered into or withdrawn from an oil well as a part of an oil well testing assembly.

FIG. 3 is a view similar to FIG. 2, and shows the parts of said tool in telescopically collapsed relation with each other, as when said testing tool assembly is resting on the bottom of the well being tested thereby, with the drill string lowered to impose its weight upon said assembly.

FIG. 4 is a view similar to FIG. 3, and illustrates the parts of said tool related to each other, as when the drill string has been lifted a short distance so as to elongate and shut the shut-in tool of said assembly and then also elongate the telescopic tool of the invention to shut the valve provided therein and thus totally capture a sample of free flowing fluid, which at the moment was flowing through and occupying the fluid sample capturing chamber of said tool.

FIGS. 2a, 3a and 4a are diagrammatic vertical sectional views of a middle portion of the aforesaid testing tool assembly, and illustrating the parts of the tools of said middle portion of said assembly in relative positions which correspond with the relative positions of the parts of the tool of the invention shown respectively in FIGS. 2, 3 and 4.

FIGS. 2b, 3b and 4b are diagrammatic fragmentary elevational views respectively of a lower portion of said oil well testing tool assembly, with the various elements of said lower portion shown as these appear respectively when the parts of the present invention are related to each other respectively as shown in FIGS. 2, 3 and 4.

FIG. 5 is a vertical sectional view drawn approximately to scale of a preferred embodiment of the present invention, with the parts thereof in telescopically collapsed relation, thereby opening the valve therein, as indicated diagrammatically in FIG. 3.

FIG. 6 is an enlarged cross-sectional view taken on the line 66 of FIG. 5, and illustrates the peripheral vertical ports in the solid head of the flow sleeve of the invention.

FIG. 7 is a fragmentary enlarged cross-sectional view taken on the line 77 of FIG. 5, and illustrates one of the two like bleeder valves of the invention which are provided respectively at the upper and lower ends of the sample capturing chamber.

FIG. 8 is a fragmentary enlarged cross-sectional view taken on the line 8-8 of FIG. 5, and illustrates the mounting of the spline key of the invention.

Description of the preferred embodiment Referring specifically to the drawings, the invention is seen to comprise a final flow period sample capturing tool 10 which performs its novel functions when united with certain other oil well testing tools to be described hereinafter, in an oil well testing tool assembly 11. This assembly is lowered into a well (not shown) while suspended on the lower end of a drill string 12. The tool 10 is connected directly to the lower end of the drill string, and in turn connects to a shut-in tool 13, which is preferably a multi-shut-in tool, as disclosed in my co-pending application Ser. No. 483,131, filed Aug. 27, 1965, now Patent No. 3,358,767. The balance of the tools in the test tool assembly 11, in the order in which these are connected serially together and suspended from the shut-in tool 13, are: a hydraulic valve tool 14, an open hole packer 15, a perforated tubing section 16 and a graphic pressure recorder carrier 17. The elements thus embraced in the tool assembly 11 are conventional with the exception of the tool 10 of the present invention, the shut-in tool 13, which may be conventional but is preferably a multishut-in tool as shown in my co-pending application above identified, and the hydraulic valve tool 14, which may be conventional but is preferably of the type disclosed in the co-pending application Ser. No. 374,685, filed July 12, 1964 by Wayne N. Sutliff, now Patent No. 3,295,607 entitled, Testing Tool. Reference will now be made to FIGS. 5-8, inclusive, for a specific description of the structure of the tool 10 of the present invention.

At its upper end the tool 10 has a top sub 18 which screws onto the lower end of the drill string 12, and has threads 19 into which is screwed the threaded upper end of a tubular mandrel 20 so as to trap 21 bar stop 25 within said sub, the latter having vertical holes 26 allowing liquid to flow freely therethrough. A relatively long keyway 27 is formed vertically in the outer surface of said mandrel, and the latter has an external annular shoulder 28 at its lower end. Internally, the mandrel has a bore 29 which terminates at its lower end in a short counterbore 30. Provided in this counterbore near its lower end is an annular recess for receiving a snap ring 31 which confines a tubular O-ring retainer 32 in said counterbore. This retainer has two external annular grooves and two internal annular grooves for retaining O-rings 33 and 34 thereon.

Slidably mounted on the mandrel 20 is a key sub 35, having at its lower end, an externally threaded pin 36 and, at its upper end, a short counterbore 40 for receiving a key retaining ring 41 and which is recessed to trap a snap ring 42 to hold said ring 41 in place. A key seat 43 is provided internally in the sub 35, a key 44 being trapped in said seat by the ring 41 with said key also extending into keyway 27 of the mandrel 20. A key knockout hole 45 is provided in the sub 35 near the lower end of said key to facilitate the removal of the latter when disassembling the tool. Screwed upwardly onto the threaded pin 36 of the sub 35 is the internally threaded upper end of a tug bular housing 46. This housing has an internal bore 47, which slidably receives the annular shoulder 28 of the mandrel 20, this housing being internally threaded at its lower end. The housing 46 is also provided with radial mudholes 48 and 49 adjacent its upper and lower ends.

Screwed upwardly into the threaded lower end of housing 46 is the externally threaded pin 50 of a bottom sub 55. This sub has an internal bore 56, and upper and lower counterbores 57 and 58. Near its upper end the counterbore 57 is recessed to receive a snap ring 59 for trapping in said counter here an O-ring retainer 60, which is properly grooved to retain external and internal O-rings 61 and 62 respectively. Counterbore 58 is recessed to mount O-rings 63 near its upper end and is internally threaded near its lower end. The bottom sub 55 terminates downwardly in a taper threaded pin 64 onto which screws the internally threaded upper end of a well fluid sample capturing tube 65.

The tool 10 is provided with an upper fluid sample bleeding device 70 which is incorporated in the bottom sub 55 in two holes 71 and 72 formed therein (FIG. 7). The hole 71 is radial and extends entirely through the wall of the sub. The hole 71 is threaded to receive a screw plug 73 to close the outer end thereof. The axis of hole 72 intersects that of hole 71 and hole 72 has counterbores 74 and 74a, the first of which intersects hole 71 to provide a valve seat 75, the counterbore 74 being tapped to receive a threaded valve plug 76 which is ground at its end to fit valve seat 75 and thus form bleeder valve 70 by which escape of fluid under pressure outwardly through hole 72 may be controlled by the rotation of said plug. Plug 76 has a head 76a which is received by counterbore 74a and has an O-ring 76b forming a seal between plug 76 counterbore 74a. A threaded counterbore 77 is provided in hole 72 on the opposite side of valve seat 75, this counterbore being normally closed by screw plug 78. The latter plug may be removed (for reasons to be made clear later) and replaced by the threaded end of a pipe 79, shown in FIG] in alignment with counterbore 77.

A flow sleeve 80 is slidably received in the lower counterbore 58 of the sub 55 so that the upper end of said sleeve engages the shoulder 85 formed at the upper end of said counterbore and makes sealing engagement with the O-rings 63 which are recessed into said counterbore. The flow sleeve 80 is externally threaded at its lower end to screw into the internally threaded lower portion of counterbore 58 of sub 55, and is provided with an extensive annular recess 86 formed in the external surface thereof, which recess communicates at its upper end with hole 71 of the bleeder valve 70 and at its lower end with a series of holes 87 which communicate between said recess and the lower end of said sleeve.

This sleeve has a blind bore 88 extending downwardly from the upper end thereof, the diameter of which bore is approximately equal to the internal diameter of O-ring retainers 32 and 60. A wash pipe 89 comprising upper and lower sections 90 and 91 which are screwed together by threads 92 slidably fits within the bore of flow sleeve and within said O-ring retainers. Trapped between the upper and lower sections and 91 of wash pipe 89 is a ring 93 which confines a coiled spring 94 between this ring and the upper end of flow sleeve 80. Holes 95, preferably four in number, are provided in the wall of flow sleeve 80 opposite the annular recess 86 thereof, and in a given radial plane, these holes being adapted to communicate with an annular recess formed externally in lower wash pipe section 91, the latter section also having a corresponding number of holes 101 which communicate between said recess and the interior of the wash pipe. The outer surface of wash pipe section 91 is grooved to allow for mounting thereon a pair of O-rings 102 which are disposed above recess 100, three O-rings 103, which are disposed below said recess and a pair of O'rings 104, which are spaced downwardly a substantial distance below the group of O-rings 103.

The upper section 90 of the wash pipe 89 is suitably recessed externally to receive a snap ring 105 which is I adapted to be engaged by the O-ring retainer 60 when the tool 10 is telescopically collapsed, so as to force the wash pipe 89 downwardly, compressing spring 94 and bringing annular recess 100 opposite holes 95 in the flow sleeve 80, thereby opening the slide valve formed by the structure of tool 10 above described, and permitting a ready flow vertically between the space within the sample capturing tube 65 and the interior of the wash pipe 89 which opens upwardly into the lower end of the drill string 12.

When the tool 10 is telescopically extended, the O-ring retainer 32 travels upwardly with the mandrel 20, thus relieving the snap ring 105 of downward pressure, and permitting the wash pipe 89 to be lifted by expansion of the spring 94, thereby withdrawing the portion of the wash pipe containing the annular recess 100 from registry with the holes 95 of the flow sleeve and thereby closing said sleeve valve and completely shutting off communication between the upper end of sample capturing tube 65 and the interior of wash pipe 89.

A lower fluid sample bleeding device is provided in the shut-in tool 13 connecting with a passage 111 therein which leads upward from the valve 112 of said tool to the lower end of a sample confining chamber 113 provided by tube 65. The bleeding device 110 is identical with the bleeding device 70 provided in tube 65 and above described.

Operation The manner in which oil tool 10 of the invention operates in performing its novel function will be manifest in the following description of a typical oil well test performed by the oil well testing tool assembly 11. While being lowered through the rotary mud filling the oil well into its testing position at the bottom of the well, the assembly 11 appears as shown in FIGS. 2, 2a and 2b. That is, each of the extensible tools 10, 13 and 14 embodied in the assembly 11 is telescopically extended so as to close the valve in that tool which controls lengthwise passage of fluid through said tool. By close observation of the rig scales which indicate the weight of the drill string and the tool assembly suspended therefrom, the rig operator becomes aware immediately when the lower end of the tool assembly 11 comes in contact with, and is supported by, the bottom of the well. From this point, the drill string is carefully lowered that distance necessary to telescopically collapse tool 10 and shut-in tool 13, thereby placing a substantial pressure on hydraulic valve tool '14 and the hydraulic dash pot embodied therein so that this pressure is transmitted through the tool 14 to the open hole packer 15, causing this to expand from the condition in which it is shown in FIG. 2b to the condition in which it is shown in FIG. 3b, in which said packer makes a fluid-tight engagement with the wall of the well and effectively shuts off any flow vertically of fluid between the packer and the well wall. The downward pressure on the packer to set this is continued until the hydraulic valve tool 14 has become telescopically collapsed so that the valves controlling vertical flow of well fluid through tools 10, 13 and 14 are all open.

The successive vertical manipulations of the drill string described in the preamble of this case are now carried out to obtain the sequence of pressure recordings desired in the test. Incidental to these manipulations and during the periods when the valves of these tools are open, and which are known as flow periods, fluid discharged by the oil-bearing strata beneath the packer enter the perforated tubing 16 below the packer and flow upwardly through the various tools of the assembly 11, including the final flow period sample trapping tool 10 of the invention, so that the sample capturing tube 65 of this tool is completely filled with this fluid. This final flow period, as already noted, concludes with the rig operator lifting on the drill string 12 so as to successively close the valves in the shut-in tool 13 and the sample trapping tool 10. The closing of the valve in hydraulic valve tool 14 may be now delayed while a final shut-in pressure is taken. The closing of hydraulic valve tool 14 at the conclusion of this final shut-in period uncovers a port 106' which admits rotary mud surrounding the tool to the central passage thereof leading downwardly through the packer 15 and outwardly through the perforated tubing 16, thereby equalizing the pressures existing above and below the packer 15. This equalization of pressures allows the packer 15 to readily contract in response to the upward pull applied thereto by the withdrawal of the drill string 12, so that the entire assembly 11 is removed from the well with the drill string.

When the testing tool assembly 11 reaches and is withdrawn from the top of the well, the fluid sample captured by the tool 10 is still completely confined in said tool so that by suitable manipulation of the bleeding devices 70 and 110, practically the entire sample, including gaseous, liquid and solid elements, is subjected to analysis, thus giving a relatively true picture of fluid flow conditions at the bottom of the well being tested.

By virtue of the fact that the sample capturing tube 65 of the present invention constitutes a separate link in the testing tool assembly 11, this tube may be made in various lengths, and thus provide the opportunity for varying the volumetric capacity of the sample confining chamber 113, whereby a sample of any desired size may be captured during a test.

The tool 10 of the present invention also provides the great advantage of assuring that each sample thus captured of whatever size represents a true cross-section of the fluid flowing freely from the oil-bearing strata being tested at the bottom of the well, by virtue of coordinately and in rapid succession shutting the valves through which said fluid is flowing into and from the sample confining chamber 113'.

I claim:

1. In an oil well test tool assembly, suspended when in use from the lower end of a drill string, the combination of: an open hole packer; means for setting said packer in an open hole to pack otf an area in said hole below said packer for test purposes and cause a flow of well fluid from said test area upwardly through said tool assembly; means located above said packer and providing a sample capturing chamber of substantial volumetric capacity; a first telescopically operable valve means provided in said assembly and interposed as a connecting telescopic link between said packer and said chamber providing means; a second telescopically operative valve means provided in said assembly and interposed as a connecting telescopic link between said chamber providing means and said drill string, both of said valve means being closed when said assembly is supended from said drill string and open when said assembly is set down on the bottom of a well to expand said packer and accomplish a testing operation, well fluid under the latter condition flowing from the test area upwardly through the packer and through said first valve means and said sample capturing chamber and filling the latter, the withdrawal of the drill string at the conclusion of the test coordinately closing said first and second valve means so as to capture and completely confine in said chamber a fluid sample, said sample chamber providing means connecting at its opposite ends to said first and second valve means but being functionally independent of the valve mechanisms of said valve means, whereby sample chamber providing means varying substantially in dimensions and volumetric capacity may be optionally employed in said assembly without modification of said valve means.

References Cited UNITED STATES PATENTS 2,388,548 l1/1945 Iurs 73-425.4 2,950,759 8/1960 Smith 1663 3,308,882 3/1967 LeBourg 166-3 2,862,561 12/1958 Teubner 73-425.4

S. CLEMENT SWISHER, Primary Examiner.

US. Cl. X.R. 166l62, 226 

